Method, device and reactor for oxidizing ferrous iron into ferric iron

Abstract

The invention relates to the technical field of direct oxidation of ferrous iron, in particular to a method, a device and a reactor for oxidizing ferrous iron into ferric iron, which comprises the following steps: properly preparing a to-be-treated solution containing ferrous iron, controlling the concentration of ferrous iron and sulfuric acid in the to-be-treated solution, and properly designing the structure of the reactor. The temperature and pressure in the reactor and the retention time of materials in the reactor are strictly controlled, and the pumping speed of the liquid to be treated into the reactor and the oxygen introduction speed are controlled, so that ferrous iron is directly oxidized into iron ions by oxygen, the oxidation rate reaches 87% or above, and the cost of directly oxidizing ferrous iron into iron ions by oxygen is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of direct oxidation of divalent iron, and in particular to a method for oxidizing divalent iron into trivalent iron, a device and a reactor thereof. Background Art

[0002] In hydrometallurgical processes, a large amount of byproducts containing ferrous ions are often produced, for example, in the process of leaching and recovering metals such as copper, nickel, cobalt, and zinc from coarse ores, concentrates, and / or tailings. In these processes, ferrous (ferrous iron) ions can also be oxidized to ferric iron, which is then returned to the process for recycling, thus realizing the resource utilization of ferrous iron.

[0003] At present, the method of oxidizing ferrous iron to ferric iron mainly includes: ① using sodium nitrite, nitric acid, etc. as a catalyst, oxidizing ferrous iron to ferric iron with air or oxygen, for example: at room temperature and pressure as disclosed in patent application No. 201610125429.2, the catalyst, oxidant, auxiliary agent, and ferrous salt are mixed, the pH is adjusted, and an aqueous solution containing iron ions is prepared to achieve direct oxidation of ferrous iron to ferric iron by oxygen or air. ② using a strong oxidant to directly oxidize ferrous iron, for example: using strong oxidants such as hydrogen peroxide and sodium chlorate to directly act on ferrous iron solution. ③ using a certain amount of reducing agent (sulfur dioxide) gas and oxygen to act on ferrous iron together to oxidize it to ferric iron, for example: using the sulfur dioxide supply rate disclosed in patent application No. 200980152716.0 to limit the oxidation rate and the concentration of dissolved oxygen in the solution to treat the optimal value, so as to achieve the controllable purpose of ferrous iron oxidation.

[0004] However, in the prior art methods of oxidizing ferrous iron to ferric iron, in order to ensure the conversion rate and quality of the conversion of ferrous iron to ferric iron, the following technical problems exist: (1) The reaction requires relatively high temperature and pressure, which places high pressure and temperature resistance requirements on the equipment, and the conversion cost is relatively high. (2) The reaction requires the addition of strong oxidants, such as potassium permanganate, hydrogen peroxide, sodium chlorate, etc., which places high requirements on the corrosion resistance of the equipment, resulting in high conversion cost; moreover, some strong oxidants are easily decomposed under high temperature and high pressure, resulting in a large amount of oxidant used, poor quality of the product obtained by treatment, and high cost. (3) It is necessary to additionally introduce reducing gas (sulfur dioxide), resulting in a high cost for the entire reaction process, and increasing the difficulty of subsequent treatment of the reducing sulfur dioxide gas.

[0005] In view of this, the present invention team combined their long-term practical research on microchannel reactors and reaction processes with the relevant theories of the oxidation of divalent iron into trivalent iron by oxygen, and launched a research project on the direct oxidation of divalent iron into trivalent iron using oxygen, providing a new idea for the oxidation of divalent iron into trivalent iron. Summary of the invention

[0006] Based on the above technical problems, the present invention provides a method for oxidizing divalent iron into trivalent iron, and a device and a reactor thereof.

[0007] The specific technical solution is:

[0008] One of the purposes of the present invention is to provide a method for oxidizing ferrous iron into ferric iron, comprising the following steps:

[0009] S1: Prepare a solution to be treated containing divalent iron, wherein Fe 2+ The concentration is 30-50g / L, and the concentration of sulfuric acid is 30-50g / L;

[0010] S2: The liquid to be treated is pumped into the reactor by a metering pump. At the same time, oxygen is introduced to control the temperature in the reactor to be 60-100°C and the pressure to be 0.6-1MPa. The mass flow rate of the liquid to be treated pumped into the reactor is 700-701g / min (in terms of FeSO 4 7H 2 O mass), and the mass flow rate of the oxygen introduced into the reactor is 6.5-9.8 g / min (in terms of O 2 The time required for the liquid to be treated to flow from the feed port of the reactor to the discharge port of the reactor is controlled to be 60-70 minutes. Preferably, the reaction temperature is 85-96°C and the reaction pressure is 0.8MPa.

[0011] By properly preparing a treated liquid containing ferrous iron, controlling the concentrations of ferrous iron and sulfuric acid in the treated liquid, strictly controlling the temperature and pressure in the reactor and the residence time of the material in the reactor, and controlling the rate at which the treated liquid is pumped into the reactor and the rate at which oxygen is introduced, the ferrous iron is directly oxidized to iron ions by oxygen, and the oxidation rate reaches more than 87%, thereby reducing the cost of directly oxidizing the ferrous iron to iron ions by oxygen. The reactor used in the invention includes a feed end and a discharge end, the feed end includes a feed reaction chamber, a second feed port arranged on the feed reaction chamber, a feed bottom hopper arranged at the bottom of the feed reaction chamber, and a first feed port arranged at the bottom of the feed bottom hopper; a feed pipe assembly is provided on the second feed port, and the second feed port is close to the side wall of the bottom of the feed reaction chamber; a jet mixing assembly is provided in the feed reaction chamber and at the position of the second feed port; the discharge end includes a discharge reaction chamber and a discharge port arranged on the side wall of the discharge reaction chamber, and the top of the discharge reaction chamber is closed; the discharge reaction chamber and the feed reaction chamber are connected as a whole via a flange, and the interior of the discharge reaction chamber is connected to the interior of the feed reaction chamber. The reactor utilizes the working principle of the microchannel reactor structure, so that the liquid to be treated can be pumped into the reactor, and the pumping pressure is used to form a jet effect. At the same time, oxygen is introduced, so that the oxygen can be injected into the feed reaction chamber during the injection process of the liquid to be treated for mixing, contact and reaction, thereby improving the mixing effect, the reaction efficiency and effect, so that the divalent iron can be directly oxidized into trivalent iron by oxygen, and the oxidation rate can reach more than 87%, which greatly reduces the difficulty and cost of converting the divalent iron into trivalent iron.

[0012] In order to ensure the conversion rate of ferrous iron to ferric iron, reduce the amount of sulfuric acid used and reduce the ferrous iron oxidation cost, preferably, in the liquid to be treated, Fe 2+ Concentration ≥ sulfuric acid concentration > 0 g / L. More preferably, in the liquid to be treated, the sulfuric acid concentration is 35 g / L, and Fe 2+ The concentration is 50g / L.

[0013] More preferably, the liquid to be treated is pumped into the reactor to form FeSO 4 7H 2 The mass flow rate of O is 700.0 g / min, and oxygen is introduced into the reactor as O 2 The mass flow rate of the mass meter is 6.8 g / min; the temperature is controlled at 90.2°C, the pressure is 0.8 MPa, the residence time is 60 min, and the oxidation rate reaches 90.2%.

[0014] More preferably, the liquid to be treated is pumped into the reactor to form FeSO 4 7H 2The mass flow rate of O is 700.0 g / min, and oxygen or air is introduced into the reactor as O 2 The mass flow rate of the mass meter is 6.8 g / min; the controlled temperature is 89.8°C, the pressure is 0.8 MPa, the residence time is 60 min, and the oxidation rate reaches 90.1%.

[0015] More preferably, the liquid to be treated is pumped into the reactor to form FeSO 4 7H 2 The mass flow rate of O is 700.1 g / min, and oxygen or air is introduced into the reactor as O 2 The mass flow rate of the mass meter is 6.7 g / min; the controlled temperature is 95.3°C, the pressure is 0.8 MPa, the residence time is 60 min, and the oxidation rate reaches 90.5%.

[0016] More preferably, the liquid to be treated is pumped into the reactor to form FeSO 4 7H 2 The mass flow rate of O is 700.2 g / min, and oxygen or air is introduced into the reactor as O 2 The mass flow rate of the mass meter is 6.5 g / min; the controlled temperature is 90.8°C, the pressure is 0.8 MPa, the residence time is 60 min, and the oxidation rate reaches 89.4%.

[0017] The invention creates a process in which ferrous iron is directly oxidized to ferric ions by oxygen. By strictly controlling the concentrations of ferrous ions, sulfuric acid, etc. in the liquid to be treated, the oxidation rate can be improved. In combination with the control of the pumping rate of the liquid to be treated and the oxygen introduction rate, and the strict control of the temperature, pressure and residence time, the oxidation rate of ferrous ions being directly oxidized to ferric ions by oxygen can be improved, and the cost of directly oxidizing ferrous ions to ferric ions by oxygen can be reduced.

[0018] In order to ensure the microchannel treatment of the mixed oxidation process of divalent iron solution and oxygen, improve the mixing effect, and improve the oxidation efficiency and oxidation rate, preferably, the injection mixing component includes a distribution plate and an injection plate, and the distribution plate and the injection plate are both arranged in the feed reaction chamber, and the injection plate is located at the upper end of the distribution plate; a suction chamber is formed between the distribution plate and the injection plate, and the suction chamber is connected with the second feed port; a plurality of injection holes are provided on the injection plate, which pass through the upper and lower surfaces of the injection plate, and a plurality of injection pipes are provided on the distribution plate, and the injection pipes are arranged corresponding to the injection holes, and the bottom end of the injection pipe passes through the lower surface of the distribution plate, and the top end of the injection pipe is located in the injection hole; there is a gap between the injection pipe and the injection hole.

[0019] In order to facilitate the adjustment of the size of the suction chamber and achieve sealing, preferably, a sealing ring is provided between the injection plate and the inner wall of the feed reaction chamber; or a sealing ring is provided between the distribution plate and the inner wall of the feed reaction chamber.

[0020] In order to connect the injection plate and the distribution plate into a whole, ensure the stability of the injection process, and realize that the size of the suction chamber can be adjusted during installation, preferably, the lower surface of the injection plate is provided with a plurality of threaded grooves, the distribution plate is provided with threaded holes corresponding to the threaded grooves, and bolts are provided in the threaded holes and the threaded grooves; or the upper surface of the distribution plate is provided with a plurality of threaded grooves, the injection plate is provided with threaded holes corresponding to the threaded grooves, and bolts are provided in the threaded holes and the threaded grooves.

[0021] In order to improve the pressure regulation within the feed pipe assembly to form a spray effect, preferably, the feed pipe assembly includes a first inlet pipe and a second inlet pipe, and a bell pipe is provided between the first inlet pipe and the second inlet pipe; the large diameter end of the bell pipe is connected to the second inlet pipe, and the small diameter end of the bell pipe is connected to the first inlet pipe; the first inlet pipe is connected to the second feed port.

[0022] The second purpose of the invention is to provide a reactor for oxidizing divalent iron into trivalent iron, including a feed end and a discharge end, the feed end including a feed reaction chamber, a second feed port arranged on the feed reaction chamber, a feed bottom hopper arranged at the bottom of the feed reaction chamber, and a first feed port arranged at the bottom of the feed bottom hopper; a feed pipe assembly is provided on the second feed port, and the second feed port is close to the side wall of the bottom of the feed reaction chamber; a jet mixing assembly is provided in the feed reaction chamber and at the position of the second feed port; the discharge end includes a discharge reaction chamber and a discharge port arranged on the side wall of the discharge reaction chamber, and the top of the discharge reaction chamber is closed; the discharge reaction chamber and the feed reaction chamber are connected to each other as a whole via a flange, and the interior of the discharge reaction chamber is connected to the interior of the feed reaction chamber.

[0023] The discharge end and the feed end structure are arranged, and a discharge reaction chamber is arranged on the discharge end, and a feed reaction chamber is arranged on the feed end. The discharge reaction chamber and the feed reaction chamber are connected as a whole via a flange, and the interior of the discharge reaction chamber is connected to the interior of the feed reaction chamber by a structure arrangement, so that the treated liquid containing divalent iron and oxygen are mixed and reacted at the feed end and then discharged from the discharge end; a jet mixing component is arranged in the feed reaction chamber and at the position of the second feed port, so that the treated liquid and oxygen can be mixed by jetting, the mixing efficiency is improved, the direct oxidation efficiency and oxidation rate of oxygen are improved, and the difficulty of oxidation treatment is reduced.

[0024] In order to extend the material residence time or increase the amount of material contained in the reactor, preferably, the reactor also includes an extension section, the discharge reaction chamber and the extension section are connected as a whole via a flange, the feed reaction chamber and the extension section are connected as a whole via a flange, and the interior of the discharge reaction chamber, the interior of the extension section and the interior of the feed reaction chamber are interconnected.

[0025] In order to avoid that the material flow in the reactor is blocked due to untimely discharge of the discharge port, thereby affecting the discharge effect, preferably, a spare discharge port is provided on the top of the discharge end.

[0026] The third purpose of the invention is to provide a device for oxidizing ferrous iron into ferric iron, comprising a reactor, a PLC control panel, a liquid tank to be processed and a gas tank, wherein the liquid tank to be processed and the reactor are connected by a pipeline, and the gas tank and the reactor are connected by a pipeline; a receiving tank is connected to the reactor via a pipeline; a metering pump is provided between the liquid tank to be processed and the reactor, and a one-way valve, a gas flow meter, a regulating valve and a pressure reducing valve are sequentially provided from the reactor to the gas tank; a heater is provided on the reactor, a temperature controller is provided between the heater and the reactor, a temperature controller is provided in the reactor, a liquid flow controller is provided between the reactor and the metering pump, a liquid flow controller is provided between the reactor and the one-way valve, and a liquid flow controller is provided between the reactor and the receiving tank; the liquid flow controller and the temperature controller are both connected to the PLC control panel; the reactor is a reactor for oxidizing ferrous iron into ferric iron as described above.

[0027] By improving and setting the reactor structure and combining the proper connection of structural components such as the liquid tank to be treated, the gas storage tank, the receiving tank, the PLC control panel, and the heater, the continuous feeding and discharging of the liquid to be treated and oxygen are realized to react, so that ferrous ions can be directly oxidized into ferric ions by oxygen, avoiding the defect of the traditional "one-pot reaction" resulting in a low oxidation rate and a high cost for oxidizing ferrous ions into ferric ions by oxygen, thereby reducing the cost of converting ferrous ions into ferric ions.

[0028] In order to avoid that the material flow in the reactor is blocked due to untimely discharge of the material from the discharge port, thereby affecting the discharge effect, preferably, the reactor is provided with a spare outlet, and the spare outlet is provided with a discharge valve.

[0029] In order to be able to observe the gas pressure in the gas storage tank and facilitate subsequent adjustment, preferably, a pressure gauge is provided on the gas storage tank.

[0030] Preferably, a pressure sensor is provided in the reactor, and the pressure sensor is connected to the PLC control panel; and a back pressure valve is provided on the pipeline between the reactor and the receiving tank, and the back pressure valve is connected to the PLC control panel; so as to facilitate timely monitoring, adjustment and control of the pressure in the reactor.

[0031] Compared with the prior art, the technical effects created by the present invention are embodied in:

[0032] The invention has a simple process flow, low requirements for equipment, a simple structure of equipment used, low cost, and can directly oxidize ferrous iron ions into iron ions by oxygen, so that the oxidation rate of ferrous iron ions into iron ions reaches more than 87%, ensuring the efficiency of ferrous iron ions into iron ions, and reducing costs. Compared with the use of strengthening agents such as hydrogen peroxide to oxidize ferrous iron ions, it not only avoids the corrosion defects of strong oxidants on equipment and reduces the requirements for equipment, but also can avoid the decomposition of similar strong oxidants such as hydrogen peroxide and the risk of explosion, improve safety, and at the same time, can also ensure the oxidation rate of ferrous iron ions into iron ions, reducing the cost of raw materials.

[0033] The invention studies and designs the reactor structure, so that the liquid to be treated can continuously enter the reactor to contact and react with oxygen, strictly controls the raw material concentration, feed rate, temperature, pressure and residence time, and achieves matching of reaction conditions. The oxidation rate of oxygen directly oxidizing divalent iron ions is improved, the cost of converting divalent iron ions into iron ions is reduced, and the conversion efficiency and effect are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to facilitate those skilled in the art to fully understand the technical solution of the present invention, the present invention is now combined with the content of the technical solution and the provided drawings, and the following description is made for the provided drawings. The directional words described in the present invention, such as: up, down, front, back, left, right, etc., are all combined and made in the face of the following drawings for easy understanding of the description, and are not a limitation of the technical solution of the present invention.

[0035] Figure 1 The overall process flow diagram is created for the present invention.

[0036] Figure 2 The present invention provides a schematic diagram of the overall structure of the reactor.

[0037] Figure 3 for Figure 2 Another schematic diagram of the structure of the embodiment.

[0038] Figure 4 The present invention provides a schematic diagram of the overall structure of a device for converting ferrous iron into ferric iron.

[0039] 1-discharge end 2-extension section 3-feed end 4-sealing ring 5-thread groove 6-bolt 7-thread hole 8-inverted funnel mouth 9-liquid tank to be treated 10-gas storage tank 11-pressure gauge 12-pressure reducing valve 13-regulating valve 14-gas flow meter 15-check valve 16-liquid flow controller 17-metering pump 18-reactor 19-discharge valve 20-receiving tank 21-PLC control panel 22-heater 23-temperature controller.

[0040] 1.1-spare discharge port 1.2-discharge port 1.3-discharge from reaction chamber.

[0041] 3.1 -feeding reaction chamber 3.2 -feeding bottom hopper 3.3 -first feeding port 3.4 -distributing plate 3.5 -injection plate 3.6 -injection hole 3.7 -intake chamber 3.8 -injection pipe 3.9 -first inlet pipe 3.10 -trumpet pipe 3.11 -second inlet pipe. DETAILED DESCRIPTION

[0042] In order to facilitate those skilled in the art to correctly understand the present invention and enable those skilled in the art to fully understand the technical content of the present invention, the technical solution of the present invention is further explained below in conjunction with specific implementation methods and drawings. However, this explanation does not limit the scope of protection required for the present invention. The scope of protection of the present invention by those skilled in the art cannot be limited to the following explanations. Any equivalent substitutions or changes made by any those skilled in the art or persons familiar with the technology in the art based on the present invention and the technical solution and inventive concept thereof should be covered within the scope of protection of the present invention.

[0043] like Figure 2 and Figure 3 As shown, in some embodiments, the ferrous iron is oxidized into ferric iron reactor, including a feed end 3 and a discharge end 1, the feed end 3 includes a feed reaction chamber 3.1, a second feed port arranged on the feed reaction chamber 3.1, a feed bottom hopper 3.2 arranged at the bottom of the feed reaction chamber 3.1, and a first feed port 3.3 arranged at the bottom of the feed bottom hopper 3.2; a feed pipe assembly is provided on the second feed port, and the second feed port is close to the side wall of the bottom of the feed reaction chamber 3.1; a jet mixing assembly is provided in the feed reaction chamber 3.1 and at the position of the second feed port; the discharge end 1 includes a discharge reaction chamber 1.3 and a discharge port 1.2 arranged on the side wall of the discharge reaction chamber 1.3, and the top of the discharge reaction chamber 1.3 is closed; the discharge reaction chamber 1.3 and the feed reaction chamber 3.1 are connected as a whole through a flange, and the interior of the discharge reaction chamber 1.3 is connected to the interior of the feed reaction chamber 3.1.

[0044] When in use, the liquid to be treated containing divalent iron is fed into the feed bottom hopper 3.2 from the first feed port 3.3, so that the liquid to be treated is continuously pumped into the feed bottom hopper 3.2, so that the pressure in the feed bottom hopper 3.2 is continuously increased, and then the liquid to be treated enters the feed reaction chamber 3.1 from the feed bottom hopper 3.2 through the injection mixing component; at the same time, another stream of material (for example: oxygen) is fed into the injection mixing component from the feed pipe component through the second feed port, and when the liquid to be treated is continuously injected into the feed reaction chamber 3.1, another stream of material (for example: oxygen) is brought into the feed reaction chamber 3.1 for mixing reaction, and as the amount of the liquid to be treated and the amount of oxygen fed in are continuously increased, the material flows from the feed reaction chamber 3.1 to the discharge reaction chamber 1.3, and then is discharged through the discharge port 1.2.

[0045] In specific applications, the reactor can be connected through components and parts to form a system suitable for liquid-liquid mixed reaction, liquid-gas mixed reaction system, for example, it can be applied to the assembly of a process device for direct oxidation of divalent iron with oxygen to trivalent iron, to obtain Figure 4 The device for oxidizing ferrous iron into ferric iron shown in the figure comprises a reactor 18, a PLC control panel 21, a liquid tank to be treated 9 and a gas storage tank 10 after application and connection and installation. The liquid tank to be treated 9 is connected to the reactor 18 by pipeline, and the gas storage tank 10 is connected to the reactor 18 by pipeline; a receiving tank 20 is connected to the reactor 18 by pipeline; a metering pump 17 is provided between the liquid tank to be treated 9 and the reactor 18, and a one-way valve 15, a gas flow meter 14, a regulating valve 13 are provided in sequence from the reactor 18 to the gas storage tank 10. and a pressure reducing valve 12; a heater 22 is provided on the reactor 18, a temperature controller 23 is provided between the heater 22 and the reactor 18, a temperature controller 23 is provided inside the reactor 18, a liquid flow controller 16 is provided between the reactor 18 and the metering pump 17, a liquid flow controller 16 is provided between the reactor 18 and the one-way valve 15, and a liquid flow controller 16 is provided between the reactor 18 and the receiving tank 20; the liquid flow controller 16 and the temperature controller 23 are both connected to the PLC control panel 21. When the device is used for direct oxidation of divalent iron and oxygen into trivalent iron, the treated liquid containing divalent iron is placed in the treated liquid tank 9, and the oxygen is placed in the gas storage tank 10; the oxygen is reduced in pressure from the gas storage tank 10 through the pressure reducing valve 12, the pressure is adjusted by the regulating valve 13, and the oxygen enters the reactor 18 through the gas flow meter 14 and the one-way valve 15; at the same time, the treated liquid is passed from the treated liquid tank 9 through the metering pump 17 into the reactor 18, so that the oxygen and the treated liquid are mixed and reacted in the reactor 18 and then discharged into the receiving tank 20. In some embodiments, the receiving tank 20 is connected to the discharge port 1.2, the first feed port 3.3 is connected to the one-way valve 15, and the feed pipe assembly is connected to the metering pump 17.

[0046] like Figure 2 and Figure 3 and Figure 4 In some embodiments, a spare discharge port 1.1 is provided on the top of the discharge end 1 to prevent the discharge port 1.2 from being untimely discharged and causing the material flow in the reactor to be blocked, thereby affecting the discharge effect. In some embodiments, a discharge valve 19 is provided on the spare discharge port 1.1.

[0047] like Figure 2 and Figure 3 As shown, in some embodiments, the reactor 18 further includes an extension section 2, the discharge reaction chamber 1.3 and the extension section 2 are connected as a whole via a flange, the feed reaction chamber 3.1 and the extension section 2 are connected as a whole via a flange, and the interior of the discharge reaction chamber 1.3, the interior of the extension section 2 and the interior of the feed reaction chamber 3.1 are interconnected. The residence time of the material in the reactor 18 and the material capacity in the reactor 18 can be adjusted. In some embodiments, the extension section 2 is a plurality of sections, for example: 1 section, 2 sections, 3 sections, 4 sections, 5 sections, 6 sections, etc.

[0048] like Figure 2 and Figure 3As shown, in some embodiments, the injection mixing assembly includes a distribution plate 3.4 and an injection plate 3.5, both of which are arranged in the feed reaction chamber 3.1, and the injection plate 3.5 is located at the upper end of the distribution plate 3.4; a suction chamber 3.7 is formed between the distribution plate 3.4 and the injection plate 3.5, and the suction chamber 3.7 is connected to the second feed port; the injection plate 3.5 is provided with a plurality of injection holes that penetrate the upper and lower surfaces of the injection plate 3.5 3.6 (for example: 1, 2, 3, 4, 5, 6, 7, etc.), a plurality of injection pipes 3.8 (for example: 1, 2, 3, 4, 5, 6, 7, etc.) are provided on the distribution plate 3.4, the injection pipes 3.8 are arranged corresponding to the injection holes 3.6, and the bottom ends of the injection pipes 3.8 pass through the lower surface of the distribution plate 3.4, and the top ends of the injection pipes 3.8 are located in the injection holes 3.6; there is a gap between the injection pipes 3.8 and the injection holes 3.6. When applied to a material mixing reaction in a gas-liquid mixed reaction system or a liquid-liquid mixed reaction system, a stream of material can enter the feed hopper 3.2 from the first feed port 3.3, and when the pressure increases as the material in the feed hopper 3.2 increases, the material can be injected into the feed reaction chamber 3.1 through the injection pipe 3.8. At the same time, another stream of material is sent from the feed pipe assembly into the suction chamber 3.7 through the second feed port, and when the material is ejected from the injection pipe 3.8 and enters the feed reaction chamber 3.1 from the injection hole 3.6, the material in the suction chamber 3.7 is brought into the feed reaction chamber 3.1 for mixing, thereby achieving material mixing. For example, when it is applied to a process of directly oxidizing a treated liquid containing divalent iron into trivalent iron using oxygen, oxygen is fed from the feed pipe assembly so as to enter the suction chamber 3.7 through the second feed port, and at the same time, the treated liquid containing divalent iron is fed from the first feed port 3.3 into the feed bottom hopper 3.2, so that the amount of treated liquid continuously flows in, thereby increasing the pressure in the feed bottom hopper 3.2, and then forming a trend of spraying the treated liquid from the injection pipe 3.8 into the injection hole 3.6, thereby driving the oxygen in the suction chamber 3.7 to flow into the feed reaction chamber 3.1, so that the oxygen and the treated liquid are mixed in the feed reaction chamber 3.1, thereby improving the uniformity of the mixing, and improving the efficiency and oxidation rate of the direct oxidation of oxygen.

[0049] like Figure 3As shown, in some embodiments, the bottom of the injection hole 3.6 is in the form of an inverted funnel mouth 8, which helps to improve the tendency of the material injected from the injection pipe 3.8 to flow in the injection hole 3.6 and suck the material in the suction chamber 3.7 into the feed reaction chamber 3.1 for mixing and reaction, thereby improving the mixing efficiency and reaction efficiency. When the divalent iron solution is directly oxidized to a trivalent iron solution by oxygen, the oxygen in the suction chamber 3.7 can be driven by the flow of the divalent iron-containing liquid to be treated injected from the injection pipe 3.8 and sucked into the feed reaction chamber 3.1.

[0050] like Figure 3 As shown, in some embodiments, a sealing ring 4 is provided between the injection plate 3.5 and the inner wall of the feed reaction chamber 3.1; and / or a sealing ring 4 is provided between the distribution plate 3.4 and the inner wall of the feed reaction chamber 3.1. The sealing between the injection plate 3.5 and / or the distribution plate 3.4 and the inner wall of the feed reaction chamber 3.1 is improved, and the material (oxygen) in the suction chamber 3.7 can be sucked into the feed reaction chamber 3.1 by the material (the treated liquid containing divalent iron) ejected from the injection pipe 3.8 for mixing, thereby improving the mixing efficiency and effect.

[0051] like Figure 3 As shown, in some embodiments, the lower surface of the injection plate 3.5 is provided with a plurality of threaded grooves 5, and the distribution plate 3.4 is provided with threaded holes 7 corresponding to the threaded grooves 5, and bolts 6 are matched with the threaded holes 7 and the threaded grooves 5; or in some embodiments, the upper surface of the distribution plate 3.4 is provided with a plurality of threaded grooves 5, and the injection plate 3.5 is provided with threaded holes 7 corresponding to the threaded grooves 5, and bolts 6 are matched with the threaded holes 7 and the threaded grooves 5, so that the injection plate 3.5 and the distribution plate 3.4 can be connected as a whole, thereby ensuring the stability of the injection process and realizing that the size of the suction chamber can be adjusted during installation.

[0052] like Figure 2 and Figure 3 As shown, in some embodiments, the feed pipe assembly includes a first feed pipe 3.9 and a second feed pipe 3.11, and a bell pipe 3.10 is provided between the first feed pipe 3.9 and the second feed pipe 3.11; the large diameter end of the bell pipe 3.10 (such as Figure 2 and Figure 3 The left end as shown in the figure) is connected to the second inlet pipe 3.11, and the small diameter end of the bell tube 3.10 (as shown in the figure) is connected to the second inlet pipe 3.11. Figure 2 and Figure 3 The right end as shown in the figure is connected to the first inlet pipe 3.9; the first inlet pipe 3.9 is connected to the second feed port, which can improve the pressure regulation in the feed pipe assembly to form a spraying effect.

[0053] like Figure 4As shown, in some embodiments, the gas storage tank 10 is provided with a pressure gauge 11 to facilitate monitoring the pressure in the gas storage tank 10.

[0054] In some embodiments, a pressure sensor is provided in the reactor 18, and the pressure sensor is connected to the PLC control panel 21; and a back pressure valve is provided on the pipeline between the reactor 18 and the receiving tank 20, and the back pressure valve is connected to the PLC control panel 21; so as to facilitate timely monitoring, adjustment and control of the pressure in the reactor.

[0055] like Figure 1 As shown, in certain embodiments, the method for oxidizing ferrous iron to ferric iron comprises the following steps:

[0056] S1: Prepare a solution to be treated containing divalent iron, wherein Fe 2+ The concentration is 30-50g / L, for example: 30g / L, 33g / L, 35g / L, 38g / L, 40g / L, 42g / L, 44g / L, 46g / L, 47g / L, 49g / L or 50g / L, etc., and the sulfuric acid concentration is 30-50g / L, for example: 30g / L, 33g / L, 35g / L, 38g / L, 40g / L, 42g / L, 44g / L, 46g / L, 47g / L, 49g / L or 50g / L, etc.;

[0057] S2: The liquid to be treated is pumped into the reactor 18 by a metering pump, and oxygen is introduced at the same time, and the temperature in the reactor 18 is controlled to be 60-100°C, for example: 60°C, 70°C, 80°C, 90°C, 100°C, etc., and the pressure is 0.6-1MPa, for example: 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa, 1MPa, etc.; the mass flow rate of the liquid to be treated pumped into the reactor 18 is 700-701g / min (in terms of FeSO 4 7H 2O mass), for example: 700g / min, 700.3g / min, 700.5g / min, 700.8g / min, 701.0g / min, etc., and the mass flow rate of the oxygen introduced into the reactor 18 is 6.5-9.8g / min (by oxygen mass), for example: 6g / min, 6.3g / min, 6.5g / min, 6.7g / min, 6.9g / min, 7.3g / min, 7.8g / min, 8g / min, 9g / min, 9.5g / min, 9.8g / min, 10g / min, etc.; the time required for the liquid to be treated to flow from the feed port of the reactor 18 to the discharge port of the reactor 18 is 60-70min, for example: 50min, 55min, 60min, 65min, 70min, etc.

[0058] In a more excellent embodiment, in the liquid to be treated, Fe 2+ Concentration ≥ sulfuric acid concentration > 0g / L. When this condition is met, it will help reduce the amount of sulfuric acid used while ensuring the oxidation rate of divalent iron ions to iron ions, so that the oxidation rate reaches more than 87%, reducing the cost of sulfuric acid use.

[0059] In a more excellent embodiment, the sulfuric acid concentration in the liquid to be treated is 35 g / L, and Fe 2+ The concentration is 50g / L.

[0060] In order to better verify the technical effect of the invention, the researchers of the invention used the reactor (such as Figure 2 or Figure 3 ) and devices (such as Figure 4 ), carried out an experimental study on the direct oxidation of a treated liquid containing divalent iron ions into iron ions by oxygen. In the experimental study, sulfuric acid was added to a ferrous sulfate heptahydrate solution to prepare a treated liquid, and the sulfuric acid concentration in the treated liquid was 35g / L and the divalent iron ion concentration was 50g / L. In the following experiments, potassium dichromate titration was used to titrate and calculate the oxidation rate, and each embodiment was obtained by taking the average value after titrating and calculating three sets of data.

[0061] Experiment 1: Comparative study of reactor selection

[0062] Example 1

[0063] The prepared solution containing divalent iron ions is treated with FeSO 4 7H 2 514.8 g of O was loaded into a barrel reactor, and 5 g of oxygen was introduced into it. The pressure of the reactor was controlled at 0.8 MPa and the temperature was 90°C. The reaction was treated for 60 minutes to obtain the product.

[0064] Example 2

[0065] The prepared solution containing divalent iron ions is treated with FeSO 4 7H 2 O mass meter is pumped into the reactor 18 at a pumping rate of 700.0g / min, and at the same time, the oxygen in the gas storage tank 10 is introduced into the reactor 18 at a rate of 6.8g / min, the pressure in the reactor 18 is controlled to be 0.8MPa, the temperature is 90.2°C, and the time (residence time) required for the treated liquid to enter the reactor 18 and be discharged from the reactor 18 is 60min.

[0066] The samples obtained in Example 1 and Example 2 were taken to measure the content of divalent iron ions and calculate the oxidation rate. The results are shown in Table 1 below.

[0067] Table 1

[0068]

[0069] As can be seen from Table 1, the reactor 18 in the invention is used to continuously pump the treated liquid containing divalent iron ions and continuously introduce oxygen for mixed reaction. Compared with the direct use of a barrel reactor "one-pot method" to directly oxidize the divalent iron solution with oxygen, the oxidation rate of divalent iron ions being directly oxidized to iron ions by oxygen is higher, which will help to improve the conversion rate of divalent iron ions.

[0070] Experiment 2: Study on the effects of residence time, feed rate and reaction temperature

[0071] Embodiment 3-6

[0072] On the basis of Example 2, the rest are the same as Example 2, the pumping rate of the liquid to be treated, the oxygen introduction rate, the pressure, the temperature and the residence time are controlled according to the changes shown in Table 2, the divalent iron ion content is measured and the oxidation rate is calculated, and the results are shown in Table 2 below.

[0073] Table 2

[0074]

[0075] It can be seen from Table 2 that under constant pressure conditions, on the basis of increasing the feed rate and stabilizing the temperature change, as the residence time shortens, the oxidation rate of divalent iron ions converted into iron ions gradually decreases; on the basis of decreasing the feed rate and stabilizing the temperature change, as the residence time increases, the oxidation rate of divalent iron ions directly oxidized by oxygen into iron ions increases, but when the residence time reaches more than 60 minutes, the oxidation rate does not change much. Therefore, when the treated liquid containing divalent iron ions is oxidized in the reactor, the residence time is determined to be 60-70 minutes.

[0076] Experiment 3: Study on the effect of reaction pressure change in the reactor

[0077] Embodiment 7-9

[0078] On the basis of Example 5, the rest are the same as Example 5, the pumping rate of the treated liquid containing divalent iron ions, the oxygen introduction rate, the pressure, the temperature and the residence time are controlled according to the changes shown in Table 3, the divalent iron ion content is measured and the oxidation rate is calculated, and the results are shown in Table 3 below.

[0079] Table 3

[0080]

[0081] It can be seen from Tables 2 and 3 that, on the basis of the oxygen introduction rate and residence time being unchanged, and the pumping rate and temperature of the treated liquid not changing much, as the pressure in the reactor increases, it will help to improve the oxidation rate of divalent iron ions being directly oxidized to iron ions by oxygen, especially when the pressure is ≥0.6MPa, the oxidation rate changes significantly better, and as the pressure increases, the oxidation rate change rate gradually decreases. At the same time, as the pressure increases, the requirements for the reactor are higher. Therefore, the reaction pressure in the reactor is controlled to 0.6-1.0MPa.

[0082] Experiment 4: Study on the effect of changing oxygen inlet rate

[0083] Examples 10-14

[0084] On the basis of Example 8, the rest are the same as Example 8, the pumping rate of the treated liquid containing divalent iron ions, the oxygen introduction rate, the pressure, the temperature and the residence time are controlled according to the changes shown in Table 4, the divalent iron ion content is measured and the oxidation rate is calculated, and the results are shown in Table 4 below.

[0085] Table 4

[0086]

[0087] It can be seen from Tables 3 and 4 that, on the basis of the small change range of the pumping rate and temperature of the treated liquid, and under the condition that the reaction pressure and residence time are unchanged, when the oxygen introduction rate is ≥6.8g / min, the oxidation rate of divalent iron ions directly oxidized to iron ions by oxygen is significantly improved, reaching more than 87%, and when the oxygen introduction rate is <6.8g / min (4.5g / min), the oxidation rate of divalent iron ions directly oxidized to iron ions by oxygen is reduced to 84.1%; at the same time, as the rate at which oxygen is introduced into the reactor increases, the oxidation rate of divalent iron ions directly oxidized to iron ions by oxygen does not change much. Therefore, in combination with the controllable difficulty required for the reactor equipment, it is advisable to control the oxygen introduction rate at 6.8-9.8g / min.

[0088] Experiment 5: Study on the effect of reaction temperature change

[0089] Examples 15-19

[0090] On the basis of Example 11, the rest are the same as Example 11, the pumping rate of the treated liquid containing divalent iron ions, the oxygen introduction rate, the pressure, the temperature and the residence time are controlled according to the changes shown in Table 5, the divalent iron ion content is measured and the oxidation rate is calculated, and the results are shown in Table 5 below.

[0091] Table 5

[0092]

[0093]

[0094] It can be seen from Table 1, Table 4 and Table 5 that, on the basis of the small change trend of the pumping rate of the treated liquid containing divalent iron ions and the oxygen feeding rate, and under the condition that the reaction pressure (0.8MPa) and the residence time (60min) remain unchanged, the temperature reaches above 85.8°C, and the oxidation rate of divalent iron ions being directly oxidized by oxygen to iron ions is significantly improved, reaching more than 87%; as the temperature gradually increases, the oxidation rate of divalent iron ions being directly oxidized by oxygen to iron ions gradually increases, but after the temperature is higher than 90.8°C, the temperature change has little effect on the oxidation rate of divalent iron ions being directly oxidized by oxygen to iron ions. Therefore, combined with the oxidation rate data obtained in Example 19, it is advisable to control the reaction temperature to 85-96°C.

[0095] In summary, in the invention, a solution containing divalent iron ions with a sulfuric acid concentration of 35 g / L and a divalent iron ion concentration of 50 g / L is used as the treated liquid, and the reactor 18 designed by the invention is used for continuous feeding and continuous discharging, so that the divalent iron ions in the treated liquid are directly oxidized to iron ions by oxygen, and the pumping rate of the treated liquid is strictly controlled to be 700.0-701.0 g / min, the oxygen introduction rate is 6.8-9.8 g / min, the reaction pressure in the reactor 18 is 0.6-1.0 MPa, the reaction temperature is 85-91 ° C, and the residence time is 60-70 min. When it can make the treated liquid containing divalent iron ions can be directly oxidized to iron ions by oxygen, and the oxidation rate reaches more than 87%, avoiding the need to use strong oxidants such as hydrogen peroxide to oxidize the divalent iron, resulting in high requirements for equipment such as reactors, high raw material costs, etc., ensuring the oxidation rate of divalent iron ions directly oxidized to iron ions by oxygen, and reducing the cost of oxidizing divalent iron ions to iron ions.

[0096] The invention creates a solution to be treated containing ferrous iron ions by introducing a continuous reaction process and a reactor 18 for continuous reaction, so that the ferrous iron ions can be directly oxidized to iron ions by oxygen, and at the same time, through strict control of the pumping rate, oxygen feeding rate, reaction pressure, reaction temperature and residence time of the solution to be treated, the oxidation rate of the ferrous iron ions directly oxidized to iron ions by oxygen is improved, the conversion rate of the ferrous iron ions to iron ions is increased, and the cost of the oxidized solution to be treated containing ferrous iron ions to iron ions is reduced. Other matters not covered in the invention can be realized by referring to the prior art or the common knowledge and conventional technical means known to those skilled in the art.

Claims

1. A method for oxidizing divalent iron into trivalent iron, characterized in that: The following steps are involved: S1: Prepare a solution to be treated containing divalent iron, wherein Fe 2+ The concentration is 30-50g / L, and the concentration of sulfuric acid is 30-50g / L; S2: The liquid to be treated is pumped into the reactor (18) by a metering pump, and at the same time, oxygen is introduced to control the temperature in the reactor (18) to be 60-100°C and the pressure to be 0.6-1MPa; the mass flow rate of the liquid to be treated pumped into the reactor (18) is 700-701g / min, and the mass flow rate of the oxygen introduced into the reactor (18) is 6.5-9.8g / min; the time required for the liquid to be treated to flow from the feed port of the reactor (18) to the discharge port of the reactor (18) is controlled to be 60-70min.

2. The method for oxidizing divalent iron into trivalent iron as claimed in claim 1, characterized in that: In the liquid to be treated, Fe 2+ Concentration ≥ sulfuric acid concentration>0g / L.

3. The method for oxidizing divalent iron into ferric iron as claimed in claim 1, characterized in that: The sulfuric acid concentration in the liquid to be treated is 35 g / L, and Fe 2+ The concentration is 50g / L.

4. The method for oxidizing divalent iron into trivalent iron as claimed in claim 1, characterized in that: The reactor comprises a feed end (3) and a discharge end (1), wherein the feed end (3) comprises a feed reaction chamber (3.1), a second feed port arranged on the feed reaction chamber (3.1), a feed bottom hopper (3.2) arranged at the bottom of the feed reaction chamber (3.1), and a first feed port (3.3) arranged at the bottom of the feed bottom hopper (3.2); a feed pipe assembly is arranged on the second feed port, and the second feed port is located on the side wall close to the bottom of the feed reaction chamber (3.1); a spray mixing assembly is arranged in the feed reaction chamber (3.1) and at the position of the second feed port; the discharge end (1) comprises a discharge reaction chamber (1.3) and a first feed port (3.3) arranged at the discharge bottom hopper (3.2); The discharge reaction chamber (1.3) has a discharge port (1.2) on the side wall of the reaction chamber (1.3), and the top of the discharge reaction chamber (1.3) is closed; the discharge reaction chamber (1.3) and the feed reaction chamber (3.1) are connected as a whole via a flange, and the interior of the discharge reaction chamber (1.3) is connected to the interior of the feed reaction chamber (3.1); or it also includes an extension section (2), the discharge reaction chamber (1.3) and the extension section (2) are connected as a whole via a flange, the feed reaction chamber (3.1) and the extension section (2) are connected as a whole via a flange, and the interior of the discharge reaction chamber (1.3), the interior of the extension section (2) and the interior of the feed reaction chamber (3.1) are connected to each other.

5. The method for oxidizing divalent iron into trivalent iron as claimed in claim 4, characterized in that: The jet mixing assembly comprises a distribution plate (3.4) and an injection plate (3.5), both of which are arranged in the feed reaction chamber (3.1), and the injection plate (3.5) is located at the upper end of the distribution plate (3.4); an inhalation cavity (3.7) is formed between the distribution plate (3.4) and the injection plate (3.5), and the inhalation cavity (3.7) is communicated with the second feed port; the injection plate (3.5) is provided with A plurality of injection holes (3.6) pass through the upper and lower surfaces of the injection plate (3.5); a plurality of injection pipes (3.8) are provided on the material distribution plate (3.4); the injection pipes (3.8) are arranged corresponding to the injection holes (3.6); the bottom ends of the injection pipes (3.8) pass through the lower surface of the material distribution plate (3.4); the top ends of the injection pipes (3.8) are located in the injection holes (3.6); and there is a gap between the injection pipes (3.8) and the injection holes (3.6).

6. The method for oxidizing divalent iron into trivalent iron as claimed in claim 5, characterized in that: A sealing ring (4) is provided between the injection plate (3.5) and the inner wall of the feed reaction chamber (3.1); or a sealing ring (4) is provided between the distribution plate (3.4) and the inner wall of the feed reaction chamber (3.1).

7. The method for oxidizing divalent iron into trivalent iron as claimed in claim 5 or 6, characterized in that: The lower surface of the injection plate (3.5) is provided with a plurality of threaded grooves (5), the distribution plate (3.4) is provided with threaded holes (7) corresponding to the threaded grooves (5), and bolts (6) are matched in the threaded holes (7) and the threaded grooves (5); or the upper surface of the distribution plate (3.4) is provided with a plurality of threaded grooves (5), the injection plate (3.5) is provided with threaded holes (7) corresponding to the threaded grooves (5), and bolts (6) are matched in the threaded holes (7) and the threaded grooves (5).

8. The method for oxidizing divalent iron into trivalent iron as claimed in claim 4, characterized in that: The feed pipe assembly comprises a first feed pipe (3.9) and a second feed pipe (3.11), and a bell pipe (3.10) is provided between the first feed pipe (3.9) and the second feed pipe (3.1); the large diameter end of the bell pipe (3.10) is connected to the second feed pipe (3.11), and the small diameter end of the bell pipe (3.10) is connected to the first feed pipe (3.9); and the first feed pipe (3.9) is connected to the second feed port.

9. A reactor for oxidizing ferrous iron to ferric iron, characterized in that: The invention comprises a feeding end (3) and a discharging end (1), wherein the feeding end (3) comprises a feeding reaction chamber (3.1), a second feeding port arranged on the feeding reaction chamber (3.1), a feeding bottom bucket (3.2) arranged at the bottom of the feeding reaction chamber (3.1), and a first feeding port (3.3) arranged at the bottom of the feeding bottom bucket (3.2); a feeding pipe assembly is arranged on the second feeding port, and the second feeding port is located on the side wall close to the bottom of the feeding reaction chamber (3.1); a spray mixing assembly is arranged in the feeding reaction chamber (3.1) and at the position of the second feeding port; the discharging end (1) comprises a discharging reaction chamber (1.3) and a discharging pipe assembly arranged at the discharging reaction chamber (3.2); The discharge reaction chamber (1.3) has a discharge port (1.2) on the side wall of the discharge reaction chamber (1.3), and the top of the discharge reaction chamber (1.3) is closed; the discharge reaction chamber (1.3) and the feed reaction chamber (3.1) are connected as a whole via a flange, and the interior of the discharge reaction chamber (1.3) is connected to the interior of the feed reaction chamber (3.1); or it also includes an extension section (2), the discharge reaction chamber (1.3) and the extension section (2) are connected as a whole via a flange, the feed reaction chamber (3.1) and the extension section (2) are connected as a whole via a flange, and the interior of the discharge reaction chamber (1.3), the interior of the extension section (2) and the interior of the feed reaction chamber (3.1) are connected to each other.

10. A device for oxidizing divalent iron into trivalent iron, characterized in that: The invention comprises a reactor (18), a PLC control panel (21), a liquid tank to be treated (9) and a gas storage tank (10), wherein the liquid tank to be treated (9) and the reactor (18) are connected by a pipeline, and the gas storage tank (10) and the reactor (18) are connected by a pipeline; a receiving tank (20) is connected to the reactor (18) via a pipeline; a metering pump (17) is provided between the liquid tank to be treated (9) and the reactor (18), and a one-way valve (15), a gas flow meter (14), a regulating valve (15) and a pressure regulating valve (16) are provided in sequence from the reactor (18) to the gas storage tank (10). valve (13) and a pressure reducing valve (12); a heater (22) is provided on the reactor (18), a temperature controller (23) is provided between the heater (22) and the reactor (18), a temperature controller (23) is provided in the reactor (18), a liquid flow controller (16) is provided between the reactor (18) and the metering pump (17), a liquid flow controller (16) is provided between the reactor (18) and the one-way valve (15), and a liquid flow controller (16) is provided between the reactor (18) and the receiving tank (20); The liquid flow controller (16) and the temperature controller (23) are both connected to the PLC control panel (21); the reactor (18) is the reactor for oxidizing divalent iron into trivalent iron as claimed in claim 9.

Images